The majority of retractors used in spinal surgery are hand held or self retaining. A few of these are force-fulcrum retractors comprising a broad metal band having at one end a fulcrum point or points which are inserted deep into the incision and lodged against bone. After such a retractor is inserted to establish a fulcrum, a weight or counterforce is applied by attaching a gauze strip to the free end of the retractor and tying the strip either to the operating table or to a weight hanging over the edge of the table, thus pulling the muscles and related tissue away from the center of the incision to expose the deep tissues such as spinal structures.
The most commonly used force-fulcrum retractor is the flat-bladed Taylor retractor which has a single, somewhat blunted tooth as its fulcrum point. Its band is curved so that the central portion rests substantially flat against the patient's back. Usually its tooth extends from the end of the retractor at an angle of about 30.degree. in the direction opposite to the direction of the curve. To accommodate various back thicknesses, suppliers typically stock pairs of Taylor retractors, which have differing lengths between their central curves and their teeth. Taylor retractors of almost identical construction are available from a number of sources, e.g., R-1080 and R-1085 of Ruggles Corp., Boston, Mass.; 2580-10 and 2580-12 of DePuy, Warsaw, Ind.; and 11-0621 and 11-0622 of Richards, Inc., Memphis, Tenn. A force-fulcrum retractor which like the Taylor comprises a centrally curved broad metal band but has two teeth is the Viboch iliac graft retractor 11-1171 of Richards, Inc. A rake retractor (which is not a force-fulcrum retractor) often has more than two teeth such as the Hibbs retractor 2577-00 of DePuy.